Question

is it possible to extend vim functionality via custom extension (preferably, written in Python)?

What I need ideally is custom command when in command mode. E.g.

ESC

:do_this

:do_that

Answer 1

vim supports scripting in python (and in perl as well, I think).

You just have to make sure that the vim distribution you are using has been compiled with python support.

If you are using a Linux system, you can download the source and then compile it with

./configure --enable-pythoninterp  make sudo make install 

Inside vim, you can type

:version 

to list the available features; if it has python support, you should see a ‘+python’ somewhere (a ‘-python’ otherwise).

Then, to check the usage of the python module, you can type

:help python 

P.S: if you’re going to compile the vim sources, make sure to check the available configure options, you might need to specify –with-python-config-dir as well.

P.P.S: to create a ‘custom command in command mode’ (if I understand correctly what you mean), you can create a function ‘MyFunction’ in a vim script (using python or the vim scripting language) and then invoke it with

:Call MyFunction() 

Check

:help user-functions 

for details